Note: Descriptions are shown in the official language in which they were submitted.
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= Attorney Docket 1 A40-7
COMMUNICATIONS CABLES WITH ISOLATORS
Field of the Invention
The present invention relates broadly to communications cable and more
particularly, to communications cable containing at least one twisted pair of
insulated conductors.
Background of the Invention
Insulated conductors such as those used in communications cable are often
provided as twisted pairs of insulated conductors having two insulated
conductors
twisted about each other to form a two conductor group. A typical assembly for
these communications cables comprises two or more twisted pairs of insulated
conductors bundled together and contained in a cable jacket. This assembly can
facilitate the installation of the cable. In addition, the cable can be
connected to
other cable components by stripping the cable jacket and making the proper
connections between the insulated conductors.
One problem associated with communications cable produced with the
conventional twisted pair assembly is that crosstalk can occur between twisted
pairs of insulated conductors that can negatively affect the signals
transmitted by
these conductors. Crosstalk may especially present a problem in high frequency
applications because crosstalk may increase logarithmically as the frequency
of the
transmission increases. Because crosstalk is affected to some degree by the
distance between twisted pairs of insulated conductors, one method of reducing
its
occurrence is to space the twisted pairs of insulated conductors apart using a
spacing means. An example of such spacing means can be found in U.S. Patent
No. 5,789,711 to Gaeris et al. which discloses a high performance data cable
which
has an interior support or star separator. Another example of such a spacing
means
can be found in U.S. Patent No. 5,969,295 to the present inventor Boucino, et
al.,
("the '295 patent") which discloses a communications cable that includes a
cable
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jacket, twisted pairs of insulated conductors, and a spacer separating the
twisted
pairs of insulated conductors. The spacer in the '295 patent extends within
the
cable jacket and has a longitudinally extending center portion and a plurality
of
wall portions radiating from the center portion thereby defining a plurality
of
compartments within the cable jacket.
Summary of the Invention
According to embodiments of the present invention, communications
cables are provided which utilize a cable jacket, twisted pairs of insulated
conductors, and a spacer separating the twisted pairs of insulated conductors.
The
spacer extends within the cable jacket and has a longitudinally extending
center
portion and a plurality of wall portions radiating from the center portion
thereby
defining a plurality of compartments within the cable jacket. In various
embodiments of the present invention, the plurality of wall portions include a
plurality of radiating sections with varying geometric shapes. The twisted
pairs of
insulated conductors are disposed in the compartments.
In embodiments of the present invention, communications cables include a
cable jacket, a spacer extending within the cable jacket and having a
longitudinally
extending center portion and plurality of longitudinally extending wall
portions
radiating from the center portion that increase in thickness from the center
portion
to the cable jacket. The spacer and the cable jacket define a plurality of
compartments within the cable jacket. One or more twisted pairs of insulated
conductors are disposed in one or more of the plurality of compartments. The
communications cable may also have a shield extending between the spacer and
the cable jacket. The twisted pairs of insulated conductors may each have a
different lay length. The plurality of longitudinally extending wall portions
may be
configured so as to define a plurality of compartments of a helical
configuration
within the cable jacket and the plurality of twisted pairs of insulated
conductors
located within the plurality of compartments may extend helically about the
longitudinal axis of the cable.
In other embodiments of the present invention, the plurality of
longitudinally extending wall portions may increase in thickness over only a
portion thereof from the center portion to the cable jacket.
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In further embodiments of the present invention, the plurality of
longitudinally extending wall portions may decrease in thickness over only a
portion thereof from the center portion to the cable jacket.
In still further embodiments of the present invention, the longitudinally
extending wall portions have a first radial section that increases in
thickness with
distance from the center portion and a second radial section that decreases in
thickness with distance from the center portion. The first radial section may
be
located between the center portion and the second radial section or the second
radial section be may located between the center portion and the first radial
section. The first radial section and the second radial section may be
configured
such that the plurality of longitudinally extending wall portions have a
convex
shaped cross-section that may be arcuate and/or include a plurality of faces.
The
first radial section and the second radial section may also be configured such
that
the plurality of longitudinally extending wall portions have a concave shaped
cross-section that may be arcuate and/or include a plurality of faces. The
first
radial section and second radial section may further be configured such that
the
plurality of longitudinally extending wall portions have a recessed portion
and/or a
ribbed portion.
In stiil other embodiments of the present invention, the longitudinally
extending wall portions may have a first section having a first thickness, a
second
section having a second thickness and a third section having a third thickness
and
located between the first section and the second section. The third thickness
is
different from the first and second thickness. In one embodiment, the first
thickness, the second thickness and the thickness of the third section are all
different. In another embodiment, the first thickness and the second thickness
may
be the same and the third thickness may be either thicker or thinner than the
first
thickness.
In still further embodiments of the present invention, the longitudinally
extending wall portions may have a sawtooth shaped cross-section having a
plurality of teeth. Each tooth may have a tooth height and a tooth spacing. In
one
embodiment, each tooth height is the same. In other embodiments, at least two
tooth heights are different. In yet other embodiments, each tooth spacing is
the
same. In still other embodiments, at least two tooth spacings are different.
In
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other embodiments, at least two tooth heights are different
and at least two tooth spacings are different.
In still other embodiments of the present
invention, the longitudinally extending wall portions may
have a first radial section and a second radial section
having a knob shaped cross-section. The knob shaped cross-
section may be any portion of a knob including a half knob
and/or a whole knob.
In a further embodiment of the present invention,
there is provided a communications cable comprising: a
cable jacket; a spacer extending within the cable jacket,
the spacer having a longitudinally extending center portion
and plurality of longitudinally extending wall portions
radiating from the center portion, the longitudinally
extending wall portions increasing in thickness from the
center portion to the cable jacket, the spacer and the cable
jacket defining a plurality of compartments within the cable
jacket; a shield extending between the spacer and the cable
jacket; and a twisted pair of insulated conductors disposed
in one of the plurality of compartments.
In another embodiment of the present invention,
there is provided a communications cable comprising: a
cable jacket; a spacer extending within the cable jacket,
the spacer having a longitudinally extending center portion
and plurality of longitudinally extending wall portions
radiating from the center portion, the longitudinally
extending wall portions increasing in thickness over only a
portion thereof from the center portion to the cable jacket,
the spacer and the cable jacket defining a plurality of
compartments within the cable jacket; and a twisted pair of
insulated conductors disposed in one of the plurality of
compartments.
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In still another embodiment of the present
invention, there is provided a communications cable
comprising: a cable jacket; a spacer extending within the
cable jacket, the spacer having a longitudinally extending
center portion and plurality of longitudinally extending
wall portions radiating from the center portion, the
longitudinally extending wall portions decreasing in
thickness over only a portion thereof from the center
portion to the cable jacket, the spacer and the cable jacket
defining a plurality of compartments within the cable
jacket; and a twisted pair of insulated conductors disposed
in one of the plurality of compartments.
In yet another embodiment of the present
invention, there is provided a communications cable
comprising: a cable jacket; a spacer extending within said
cable jacket, the spacer having a longitudinally extending
center portion and plurality of longitudinally extending
wall portions radiating from said center portion, the
longitudinally extending wall portions having a first radial
section that increases in thickness with distance from the
center portion and a second radial section that decreases in
thickness with distance from the center portion, the spacer
and the cable jacket defining a plurality of compartments
within the cable jacket; and a twisted pair of insulated
conductors disposed in at least one of the compartments.
In an even further embodiment of the present
invention, there is provided a communications cable
comprising: a cable jacket; a spacer extending within said
cable jacket, the spacer having a longitudinally extending
center portion and plurality of longitudinally extending
wall portions radiating from said center portion, the
longitudinally extending wall portions including a first
section having a first thickness, a second section having a
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second thickness and a third section having a third
thickness, the third thickness being different from the
first and second thickness, the third section located
between the first section and the second section, the spacer
and the cable jacket defining a plurality of compartments
within the cable jacket; and a twisted pair of insulated
conductors disposed in at least one of the compartments.
In a still further embodiment of the present
invention, there is provided a communications cable
comprising: a cable jacket; a spacer extending within said
cable jacket, the spacer having a longitudinally extending
center portion and plurality of longitudinally extending
wall portions radiating from said center portion, the
longitudinally extending wall portions having a sawtooth
shaped cross-section including a plurality of teeth, each
tooth having a tooth height and a tooth spacing, the spacer
and the cable jacket defining a plurality of compartments
within the cable jacket; and a twisted pair of insulated
conductors disposed in at least one of the compartments.
In a yet further embodiment of the present
invention, there is provided a communications cable
comprising: a cable jacket; a spacer extending within said
cable jacket, the spacer having a longitudinally extending
center portion and plurality of longitudinally extending
wall portions radiating from said center portion, the
longitudinally extending wall portions including a knob
shaped cross-section, the spacer and the cable jacket
defining a plurality of compartments within the cable
jacket; and a twisted pair of insulated conductors disposed
in at least one of the compartments.
In another embodiment of the present invention,
there is provided a communications cable comprising: a
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cable jacket; a spacer extending within said cable jacket,
the spacer having a longitudinally extending center portion
and plurality of longitudinally extending wall portions
radiating from said center portion, the longitudinally
extending wall portions having a convex shaped cross-
section, the spacer and the cable jacket defining a
plurality of compartments within the cable jacket; and a
twisted pair of insulated conductors disposed in at least
one of the compartments.
In a still further embodiment of the present
invention, there is provided a communications cable
comprising: a cable jacket; a spacer extending within said
cable jacket, the spacer having a longitudinally extending
center portion and plurality of longitudinally extending
wall portions radiating from said center portion, the
longitudinally extending wall portions having a concave
shaped cross-section, the spacer and the cable jacket
defining a plurality of compartments within the cable
jacket; and a twisted pair of insulated conductors disposed
in at least one of the compartments.
Brief Description of the Drawings
Figure 1 is a perspective view of embodiments of
communications cables of the present invention;
Figure 2 is a cross-sectional view of
communications cables of Figure 1 taken along line 2-2;
Figure 3 is a cross-sectional view of other
embodiments of communications cables according to the
present invention;
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Figure 4 is a cross-sectional view of further
embodiments of communications cables according to the
present invention;
Figure 5 is a cross-sectional view of still other
embodiments of communications cables according to the
present invention;
Figure 6 is a cross-sectional view of still
further embodiments of communications cables according to
the present invention;
Figure 7 is a cross-sectional view of still other
embodiments of communications cables according to the
present invention;
Figure 8 is a cross-sectional view of still
further embodiments of communications cables according to
the present invention.
Detailed Description of the Preferred Embodiments
The present invention now will be described more
fully hereinafter with reference to the accompanying
drawings, in which preferred embodiments of the invention
are shown. This invention may, however, be embodied in many
different forms and should not be construed as limited to
the embodiments set forth herein. Instead, these
embodiments are provided so that this disclosure will be
thorough and complete, and will fully convey the scope of
the invention to those skilled in the art. It will be
understood that when an element (e.g., cable jacket) is
referred to as being "connected to" another element, it can
be directly connected to the other
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Attorney Docket 1. -4040-7
element or intervening elements may also be present. In contrast, when an
element
is referred to as being "directly connected to" another element, there are no
intervening elements present. Like numbers refer to like elements throughout.
Referring now to Figures 1 and 2, embodiments of communications cables
according to the present invention will now be described. The illustrated
communications cable 10 includes a cable jacket 12, a spacer 14, a plurality
of
twisted pairs of insulated conductors 20, 22, 24, 26, a shield 16 and a
plurality of
compartments 40, 42, 44, 46. The cable j acket 12 surrounds the spacer 14, the
shield 16 and the twisted pairs 20, 22, 24, 26 and is preferably tubular in
shape.
Preferably, the cable jacket 12 is made of a flexible polymer material and is
formed
by melt extrusion. As will be understood by those of skill in the art, any of
the
polymer materials conventionally used in cable construction may be suitably
employed including, but not limited to, polyvinylchloride, polyvinylchloride
alloys, polyethylene, polypropylene and flame retardant materials such as
fluorinated polymers. Moreover, other materials and/or fabrication methods may
be used. Preferably, the cable jacket 12 is extruded to a thickness of between
15
and 25 mils (thousandths of an inch) which may facilitate stripping the cable
jacket
12 away from the twisted pairs 20, 22, 24, 26. However, other dimensions may
be
used.
With reference to Figure 1, the shield 16 is located between the spacer 14
and the cable jacket 12 and is preferably longitudinally coextensive with the
cable
jacket 12. The shield 16 may be made from a wide variety of known conductive
and/or nonconductive materials such as nonconductive polymeric tape;
conductive
tape; braid; a combination of nonconductive polymeric tape, conductive tape
and/or braid; and/or other such materials as will be understood to one of
skill in the
art using conventional fabrication techniques. The shield 16 may include one
or
more layers of material 16a, 16b and may be applied longitudinally, helically,
etc.
and/or may be braided as will be understood to one of skill in the art. As
will be
understood by one of skill in the art, the shield 16 can be omitted from the
communications cable 10.
As shown in Figure 1, the spacer 14 is situated within and is longitudinally
coextensive with the cable jacket 12. As illustrated in Figure 2, the spacer
14
includes a longitudinally extending center portion 30 and a plurality of
longitudinally extending wall portions 32, 34, 36, 38 radiating from the
center
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Attorney Docket 1 -4040-7
portion 30. As illustrated in Figure 2, the wall portions 32, 34, 36, 38
preferably
increase in thickness from the center portion 30 to the cable jacket 12. The
spacer
14 and the cable jacket 12 may define a plurality of compartments 40, 42, 44,
46 in
which the twisted pairs 20, 22, 24, 26 may be located. Alternatively, the
plurality
of compartments may be defined by the spacer 14 and the shield 16. Each of the
compartments 40, 42, 44, 46 is preferably of sufficient size to receive a
corresponding twisted pair 20, 22, 24, 26. The communications cable 10
preferably has at least four compartments 40, 42, 44, 46 to receive at least
four
respective twisted pairs 20, 22, 24, 26. Although the illustrated
communications
cable 10 has four compartments 40, 42, 44, 46 which can receive four twisted
pairs
20, 22, 24, 26, it will be understood by those skilled in the art that the
communications cable 10 may have two, three, four or more compartments 40, 42,
44, 46 for receiving a plurality of twisted pairs 20, 22, 24, 26 and that
every
compartment 40, 42, 44, 46 need not include a twisted pair 20, 22, 24, 26.
As shown in Figure 1, the insulated conductors 27 of each twisted pair 20,
22, 24, 26 are twisted helically around one another. Preferably, the twisted
pairs
20, 22, 24, 26 are typically twisted at a lay length of between about 0.25 and
about
1.50 inches and each of the twisted pairs 20, 22, 24, 26 preferably has a
different
lay length from any other twisted pair 20, 22, 24, 26 of the communications
cable
10.
As shown in Figure 1 with reference to only one twisted pair 24 for
purposes of illustration, each insulated conductor 27 in the twisted pair 24
comprises a conductor 28 surrounded by a layer of an insulated material 29.
The
conductor 28 may be a metallic wire of any of the well-known metallic
conductors
used in wire and cable applications, such as copper, aluminum, copper-clad
aluminum and/or copper-clad steel. Preferably, the wire is 18 to 26 AWG gauge.
The conductor 28 is surrounded by a layer of the insulating materia129.
Preferably, the thickness of the insulating materia129 is less than about 25
mil,
preferably less than about 15 mil, and for certain applications even less than
about
10 mil. The insulating materia129 may also be foamed or expanded through the
use of a blowing or foaming agent. Suitable insulating materials for the
insulated
conductor 27 include polyvinylchloride, polyvinylchloride alloys,
polyethylene,
polypropylene, and flame retardant materials such as fluorinated polymers.
Exemplary fluorinated polymers for use in the invention include fluorinated
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Attorney Docket 1 )040-7
ethylene-propylene (FEP), ethylenetrifluoroethylene (ETFE), ethylene
chlorotrifluoroethylene (ECTFE), perfluoroalkoxypolymers (PFA's), and mixtures
thereof. Exemplary PFA's include copolymers of tetrafluoroethylene and
perfluoropropylvinylether (e.g., Teflon PFA 340) and copolymers of
tetrafluoroethylene and perfluoromethylvinylether (MFA copolymers which are
available from Ausimont S.p.A.). In addition, the insulating materia129 can
contain conventional additives such as pigments, nucleating agents, thermal
stabilizers, acid acceptors, processing aids, and/or flame retardant
compositions
(e.g., antimony oxide). If desired, the insulating materia129 used for the
insulated
. conductor 27 may not be the same for each twisted pair 20, 22, 24, 26. For
example, three of the twisted pairs 20, 22, 24, 26 may be constructed using a
foamed polyvinylchloride insulating material 29 while the fourth twisted pair
20,
22, 24, 26 is constructed using a different insulating material 29 such as a
foamed
FEP. Other materials, dimensions and/or fabrication techniques for the
conductors
and/or insulating materials 29 may be used.
As shown in Figure 1, the wall portions 32, 34, 36, 38 of the
communications cable 10 may be configured so as to define longitudinally
extending passageways or compartments 40, 42, 44, 46 of a helical
configuration
within the cable jacket 12 so that the respective twisted pairs 20, 22, 24, 26
located
within the compartments 40, 42, 44, 46 extend helically around the
longitudinal
axis of the communications cable 10. Typically, the spacer 14 and the twisted
pairs 20, 22, 24, 26 are twisted to provide this helical configuration thereby
holding these cable components together. Furthermore, this helical
configuration
may improve the impedance uniformity of the cable by maintaining uniformity of
spacing of the respective twisted pairs 20, 22, 24, 26 despite bending of the
communications cable 10. The cable components may be !twisted helically at a
predetermined lay length defined as the length it takes for one of the cable
components (e.g., one twisted pair 20, 22, 24, 26) to make one complete
helical
turn. Preferably, the lay length is between about 3 and about 8 inches.
However,
other lay lengths may be used.
Figures 1 and 2 illustrate embodiments of the invention wherein the spacer
14 is separate from the shield 16. In this configuration, the wall portions
32, 34,
36, 38 radiate from the center portion 30 and terminate proximate to the
shield 16.
The communications cable 10 illustrated in Figures 1 and 2 may be manufactured
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= Attomey Docket 1 A40-7
by extruding the spacer 14 using a suitable polymer material, such as the
materials
described above for use in the cable jacket 12. The spacer 14 may also
comprise
conductors such as metal and/or semiconductors such as carbon. The spacer 14
may be formed into a desired shape as it exits the extruder and is cooled or
quenched to harden the spacer 14. The spacer 14 may then be bunched with four
twisted pairs 20, 22, 24, 26 such that the twisted pairs 20, 22, 24, 26 are
oriented in
the compartments 40, 42, 44, 46 of the spacer 14. The spacer 14 and the
twisted
pairs 20, 22, 24, 26 may also be twisted helically during the bunching process
which may increase the impedance uniformity of the communications cable 10.
Once the spacer 14 and the twisted pairs 20, 22, 24, 26 are bunched, the
shield 16
may be applied and the cable jacket 12 may then be extruded around the shield
16,
spacer 14 and twisted pairs 20, 22, 24, 26 to form the communications cable
10.
Other manufacturing techniques may also be used.
Although the spacer 14 of the embodiment of Figures 1 and 2 is not
connected to the shield 16, the wall portions 32, 34, 36, 38 of the spacer 14
may be
connected to the shield 16. The spacer 14 may be connected to the shield 16,
for
example, by designing the spacer 14 so that it extends slightly beyond the
twisted
pairs 20, 22, 24, 26 and constructing the shield 16 from heat bonded foil tape
which, when heated through the cable jacket extrusion process, may become
bonded to the spacer 14. Other manufacturing techniques may also be used.
As mentioned above, the shield 16 may be omitted from the
communications cable 10. Techniques from manufacturing a communications
cable without a shield, but with the spacer either connected or not connected
to the
cable jacket, are disclosed in U. S. Patent No. 5,969,295 to the present
inventor
Boucino, et al., entitled "Twisted Pair Communications Cable," which patent is
hereby incorporated by reference as if fully set forth herein.
With reference to Figure 3, a communications cable 110 according to
further embodiments of the present invention will now be described. The
communications cable 110 includes a cable jacket 112, a spacer 114, a
plurality of
twisted pairs of insulated conductors 120, 122, 124, 126, a shield 116 and a
plurality of compartments 140, 142, 144, 146. It will, however, be understood
that
the shield 116 may be omitted. The cable jacket 112, the plurality of twisted
pairs
of insulated conductors 120, 122, 124, 126, the shield 116 and the plurality
of
compartments 140, 142, 144, 146 may generally be constructed in the same
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manner as the cable jacket 10, the plurality of twisted pairs of insulated
conductors
20, 22, 24, 26, the shield 16 and the plurality of compartments 40, 42, 44, 46
described above with reference to the communications cable 10. Accordingly, a
detailed description thereof need not be repeated.
As shown in Figure 3, the spacer 114 is situated within and is
longitudinally coextensive with the cable jacket 112. The spacer 114 may
comprise the same materials and may be fabricated using the same fabrication
techniques that were discussed in connection with the spacer 14. As
illustrated in
Figure 3, the spacer 114 includes a longitudinally extending center portion
130
and a plurality of longitudinally extending wall portions 132, 134, 136, 138
radiating from the center portion 130. Each individual wall portion 132, 134,
136,
138 preferably includes a plurality of radial sections 138a, 138b wherein each
individual radial section 138a, 138b may be of constant thickness, or may
increase
in thickness or decrease in thickness with distance from the center portion
130. As
will be understood to one of skill in the art, the change in thickness of the
radial
sections that increase or decrease in thickness may be linear or non-linear,
and may
be continuous or discontinuous. In the embodiment illustrated in Figure 3,
each
wall portion 132, 134, 136, 138 includes two radial sections 138a, 138b that
are
configured such that the wall portions 132, 134, 136, 138 first decrease in
thickness with distance from the center portion 130 and then increase in
thickness
with distance from the center portion 130. As used herein, the term
"configured"
refers to the shape of a radial section 138a, 138b and/or the location of the
radial
sections 138a, 138b relative to one another.
As will be understood to one of skill in the art, the plurality of radial
sections 138a, 138b may be configured to produce wall portions 132, 134, 136,
138 with a wide variety of shapes including, but not limited to,
configurations
where the wall portions 132, 134, 136, 138 first decrease in thickness with
distance
from the center portion 130 and then increase in thickness with distance from
the
center portion 130, configurations where the wall portions 132, 134, 136, 138
increase in thickness over only a portion thereof with the remaining portion
being
of constant thickness, and configurations where the wall portions 132, 134,
136,
138 decrease in thickness over only a portion thereof with remaining portion
being
of constant thickness. As will be understood to one of skill in the art, two
or more
radial sections 138a, 138b can be used. These embodiments may allow for better
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control of the location of the twisted pairs within the compartments which may
provide better separation between the twisted pairs which may, in turn,
improve
crosstalk performance at the possible expense of decreasing the flexibility of
the
cable, which may depend on the amount of material used in the center portion,
and
increasing the possibility that the wall portions may fold over against the
twisted
pairs which may adversely affect the impedance and return loss. These
embodiments may also provide increased surface contact between the spacer and
the cable jacket or, if included, the shield, which may better protect the
twisted
pairs during the process of stripping the cable jacket and/or shield away.
With reference to Figure 4, a communications cable 210 according to
further embodiments of the present invention will now be described. The
communications cable 210 includes a cable jacket 212, a spacer 214, a
plurality of
twisted pairs of insulated conductors 220, 222, 224, 226, a shield 216 and a
plurality of compartments 240, 242, 244, 246. It will, however, be understood
that
the shield 216 may be omitted. The cable jacket 212, the plurality of twisted
pairs
of insulated conductors 220, 222, 224, 226, the shield 216 and the plurality
of
compartments 240, 242, 244, 246 may generally be constructed in the same
manner as the cable jacket 10, the plurality of twisted pairs of insulated
conductors
20, 22, 24, 26, the shield 16 and the plurality of compartments 40, 42, 44, 46
described above with reference to the communications cable 10. Accordingly, a
detailed description thereof need not be repeated.
As shown in Figure 4, the spacer 214 is situated within and is
longitudinally coextensive with the cable jacket 212. The spacer 214 may
comprise the same materials and may be fabricated using the same fabrication
techniques that were discussed in connection with the spacer 14. As
illustrated in
Figure 4, the spacer 214 includes a longitudinally extending center portion
230
and a plurality of longitudinally extending wall portions 232, 234, 236, 238
radiating from the center portion 230. Each individual wall portion 232, 234,
236,
238 preferably includes plurality of radial sections 238a, 238b wherein each
individual radial section 238a, 238b may be of constant thickness, or may
increase
in thickness or decrease in thickness with distance from the center portion
230. As
will be understood to one of skill in the art, the change in thickness of the
radial
sections that increase or decrease in thickness may be linear or non-linear,
and may
be continuous or discontinuous. In the embodiment illustrated in Figure 4,
each
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wall portion 232, 234, 236, 238 includes two radial sections 238a, 238b which
are
configured such that the wall portions 232, 234, 236, 238 have a convex shaped
cross-section.
As will be understood by one of skill in the art, the plurality of radial
sections 238a, 238b may also be configured to produce wall portions 232, 234,
236, 238 with a wide variety cross-sectional shapes including, but not limited
to,
configurations that have a concave shaped cross-section and configurations
that
have a cross-section that alternates between convex shaped and concave shaped.
As will also be understood by one of skill in the art, the convex and concave
cross-
sections may be arcuate in shape or may be formed from a plurality of faces.
As
will be understood to one of skill in the art, two or more radial sections
238a, 238b
can be used. These embodiments may allow for better control of the location of
the twisted pairs within the compartments which may provide better separation
between the twisted pairs which may, in turn, improve crosstalk performance at
the
possible expense of requiring more material which may increase manufacturing
cost and may decrease cable flexibility. These embodiments may also be easier
to
manufacture.
With reference to Figure 5, a communications cable 310 according to
further embodiments of the present invention will now be described. The
communications cable 310 includes a cable jacket 312, a spacer 314, a
plurality of
twisted pairs of insulated conductors 320, 322, 324, 326, a shield 316 and a
plurality of compartments 340, 342, 344, 346. It will, however, be understood
that
the shield 316 may be omitted. The cable jacket 312, the plurality of twisted
pairs
of insulated conductors 320, 322, 324, 326, the shield 316 and the plurality
of
compartments 340, 342, 344, 346 may generally be constructed in the same
manner as the cable jacket 10, the plurality of twisted pairs of insulated
conductors
20, 22, 24, 26, the shield 16 and the plurality of compartments 40, 42, 44, 46
described above with reference to the communications cable 10. Accordingly, a
detailed description thereof need not be repeated.
As shown in Figure 5, the spacer 314 is situated within and is
longitudinally coextensive with the cable jacket 312. The spacer 314 may
comprise the same materials and may be fabricated using the same fabrication
techniques that were discussed in connection with the spacer 14. As
illustrated in
Figure 5, the spacer 314 includes a longitudinally extending center portion
330
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CA 02349327 2001-05-31
Attorney Docket 9040-7
and a plurality of longitudinally extending wall portions 332, 334, 336, 338
radiating from the center portion 330. Each individual wall portion 332, 334,
336,
338 preferably includes a plurality of radial sections 338a, 338b ... 338n
wherein
each individual radial section 338a, 338b ... 338n may be of constant
thickness,
or may increase in thickness or decrease in thickness with distance from the
center
portion 330. As will be understood to one of skill in the art, the change in
thickness of the radial sections that increase or decrease in thickness may be
linear
or non-linear, and may be continuous or discontinuous.
In the embodiment illustrated in Figure 5, the plurality of radial sections
338a, 338b ... 338n are configured such that the wall portions 332, 334, 336,
338
have a saw-toothed shaped cross-section wherein each individual tooth has a
height
X, Y and the teeth are spaced at a distance E, F. As will be understood by one
of
skill in the art, the height X, Y of each individual tooth may be equal to or
may
vary from the height X, Y of any other tooth and the distance E, F between
teeth
may be equal to or may vary from the distance E, F between any two other
teeth.
It will also be understood that the number of teeth may vary from the number
shown in Figure 5, and that the number of teeth may vary between wall portions
332, 334, 336, 338. These embodiments may allow for better control of the
location of the twisted pairs within the compartznents which may provide
better
separation between the twisted pairs which, in turn, may improve crosstalk
performance. Additionally, these embodiments may produce a more flexible cable
due to the possible accordion affect that may take place within the wall
portions,
all at the possible expense of adversely affecting manufacturing stability and
possibly creating pinch points on the twisted pairs which may degrade
impedance
and return loss performance.
With reference to Figure 6, a communications cable 410 according to
further embodiments of the present invention will now be described. The
communications cable 410 includes a cable jacket 412, a spacer 414, a
plurality of
twisted pairs of insulated conductors 420, 422, 424, 426, a shield 416 and a
plurality of compartments 440, 442, 444, 446. It will, however, be understood
that
the shield 416 may be omitted. The cable jacket 412, the plurality of twisted
pairs
of insulated conductors 420, 422, 424, 426, the shield 416 and the plurality
of
compartments 440, 442, 444, 446 may generally be constructed in the same
manner as the cable jacket 10, the plurality of twisted pairs of insulated
conductors
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CA 02349327 2001-05-31
Attorney Docket )040-7
20, 22, 24, 26, the shield 16 and the plurality of compartments 40, 42, 44, 46
described above with reference to the communications cable 10. Accordingly, a
detailed description thereof need not be repeated.
As shown in Figure 6, the spacer 414 is situated within and is
longitudinally coextensive with the cable jacket 412. The spacer 414 may
comprise the same materials and may be fabricated using the same fabrication
techniques that were discussed in connection with the spacer 14. As
illustrated in
Figure 6, the spacer 414 includes a longitudinally extending center portion
430
and a plurality of longitudinally extending wall portions 432, 434, 436, 438
radiating from the center portion 430. Each individual wall portion 432, 434,
436,
438 preferably includes plurality of radial sections 438a, 438b wherein each
individual radial section 438a, 438b may be of constant thickness, may
increase in
thickness or decrease in thickness with distance from the center portion 430,
or
may have a knob shaped cross-section. As will be understood to one of skill in
the
art, the change in thickness of the radial sections that increase or decrease
in
thickness may be linear or non-linear, and may be continuous or discontinuous.
In
the embodiment illustrated in Figure 6, each wall portion 432, 434, 436, 438
includes two radial sections 438a, 438b with the first radial section 438a
being of
constant thickness and the second radial section 438b having a knob shaped
cross-
section and a size G, H, I, J. Although the knob shaped radial section in
Figure 6
is a whole knob, one of skill in the art will understand that the knob shaped
radial
section may consist of only a portion of a knob including a half knob and that
the
size G, H, I, J of a knob may be the same or may vary between knobs.
As will be also understood by one of skill in the art, the plurality of radial
sections 438a, 438b may also be configured to produce wall portions 432, 434,
436, 438 with a wide variety of shapes including, but not limited to,
configurations
that include multiple knob shaped radial sections and configurations that
include
knob shaped radial sections combined with radial sections that increase in
thickness and/or radial sections that decrease in thickness and/or radial
sections of
constant thickness. It will also be understood that the knobs need not be at
the
ends of the spacer. These embodiments may restrain the twisted pairs from
becoming too close to the cable jacket which may make the cable easier to
manufacture at the possible expense of allowing the twisted pairs to move
closer
together which may decrease crosstalk performance. These embodiments may also
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CA 02349327 2001-05-31
Attorney Docket 1 ~040-7
provide increased surface contact between the spacer and the cable jacket or,
if
included, the shield, which may better protect the twisted pairs during the
process
of stripping the cable jacket and/or shield away, and may reduce the
possibility that
the twisted pairs will slip out of their respective compartments during
manufacturing which may increase the stability of the cable.
With reference to Figure 7, a communications cable 510 according to
further embodiments of the present invention will now be described. The
communications cable 510 includes a cable jacket 512, a spacer 514, a
plurality of
twisted pairs of insulated conductors 520, 522, 524, 526, a shield 516 and a
plurality of compartments 540, 542, 544, 546. It will, however, be understood
that
the shield 516 may be omitted. The cable jacket 512, the plurality of twisted
pairs
of insulated conductors 520, 522, 524, 526, the shield 516 and the plurality
of
compartments 540, 542, 544, 546 may generally be constructed in the same
manner as the cable jacket 10, the plurality of twisted pairs of insulated
conductors
20, 22, 24, 26, the shield 16 and the plurality of compartments 40, 42, 44, 46
described above with reference to the communications cable 10. Accordingly, a
detailed description thereof need not be repeated.
As shown in Figure 7, the spacer 514 is situated within and is
longitudinally coextensive with the cable jacket 512. The spacer 514 may
comprise the same materials and may be fabricated using the same fabrication
techniques that were discussed in connection with the spacer 14. As
illustrated in
Figure 7, the spacer 514 includes a longitudinally extending center portion
530
and a plurality of longitudinally extending wall portions 532, 534, 536, 538
radiating from the center portion 530. Each individual wall portion 532, 534,
536,
538 preferably includes plurality of radial sections 538a, 538b, 538c wherein
each
individual radial section 538a, 538b, 538c may be of constant thickness, or
may
increase in thickness or decrease in thickness with distance from the center
portion
530. As will be understood to one of skill in the art, the change in thickness
of the
radial sections that increase or decrease in thickness may be linear or non-
linear,
and may be continuous or discontinuous. In the embodiment illustrated in
Figure
7, each wall portion 532, 534, 536, 538 includes three radial sections 538a,
538b,
538c which are configured such that the middle radial section 538b is thicker
than
the other two radial sections 538a, 538c thus forming a ribbed portion.
Alternatively, the embodiment illustrated in Figure 7 may also be described as
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CA 02349327 2001-05-31 Attorney Docket 1. _. 9040-7
including two radial sections 538d, 538e, one that increases in thickness in a
discontinuous manner 538d with distance from the center portion 530 and one
that
decreases in thickness in a discontinuous manner 538e with distance from the
center portion 530, which are configured such that the wall portions 532, 534,
536,
538 have a ribbed portion.
As will be understood by one of skill in the art, the width B of a ribbed
portion for any one wall portion 532, 534, 536, 538 may be the same as or may
vary from the width B of a ribbed portion for any other wall portion 532, 534,
536,
538. It will also be understood that there may be multiple ribbed portions.
These
embodiments may increase twisted pair separation by increasing the thickness
of
the wall portions located adjacent to the twisted pairs which may improve
crosstalk
performance at the possible expense of moving the twisted pairs undesirably
close
to the cable jacket and/or shield which may adversely affect return loss,
impedance
and attenuation. These embodiments may also reduce the amount of material in
the center portion which may increase cable flexibility.
With reference to Figure 8, a communications cable 610 according to
further embodiments of the present invention will now be described. The
communications cable 610 includes a cable jacket 612, a spacer 614, a
plurality of
twisted pairs of insulated conductors 620, 622, 624, 626, a shield 616 and a
plurality of compartments 640, 642, 644, 646. It will, however, be understood
that
the shield 616 may be omitted. The cable jacket 612, the plurality of twisted
pairs
of insulated conductors 620, 622, 624, 626, the shield 616 and the plurality
of
compartments 640, 642, 644, 646 may generally be constructed in the same
manner as the cable jacket 10, the plurality of twisted pairs of insulated
conductors
20, 22, 24, 26, the shield 16 and the plurality of compartments 40, 42, 44, 46
described above with reference to the communications cable 10. Accordingly, a
detailed description thereof need not be repeated.
As shown in Figure 8, the spacer 614 is situated within and is
longitudinally coextensive with the cable jacket 612. The spacer 614 may
comprise the same materials and may be fabricated using the same fabrication
techniques that were discussed in connection with the spacer 14. As
illustrated in
Figure 8, the spacer 614 includes a longitudinally extending center portion
630
and a plurality of longitudinally extending wall portions 632, 634, 636, 638
radiating from the center portion 630. Each individual wall portion 632, 634,
636,
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CA 02349327 2001-05-31
Attorney Docket 1. . 9040-7
638 preferably includes plurality of radial sections 638a, 638b, 638c wherein
each
individual radial section 638a, 638b, 638c may be of constant thickness, or
may
increase in thickness or decrease in thickness with distance from the center
portion
630. As will be understood to one of skill in the art, the change in thickness
of the
radial sections that increase or decrease in thickness may be linear or non-
linear,
and may be continuous or discontinuous. In the embodiment illustrated in
Figure
8, each wall portion 632, 634, 636, 638 includes three radial sections 638a,
638b,
638c which are configured such that the middle radial section 638b is thinner
than
the other two radial sections 638a, 638c thus forming a recessed portion.
Alternatively, the embodiment illustrated in Figure 8 may also be described as
including two radial sections 638d, 638e, one that decreases in thickness in a
discontinuous manner 638d with distance from the center portion 630 and one
that
increases in thickness in a discontinuous manner 638e with distance from the
center portion 630, which are configured such that the wall portions 632, 634,
636,
638 have a recessed portion.
As will be understood by one of skill in the art, the width A of a recessed
portion for any one wall portion 632, 634, 636, 638 may be the same as or may
vary from the width A of a recessed portion for any other wall portion 632,
634,
636, 638. It will also be understood that there may be multiple recessed
portions.
These embodiments may allow for better control of the location of the twisted
pairs
within the compartments which may provide better separation between the
twisted
pairs which, in turn, may improve crosstalk performance at the possible
expense of
adversely affecting return loss. These embodiments may also use more material
which may decrease cable flexibility, and may increase the probability that
the wall
portions will fold over which may allow the twisted pairs to slip into an
adjoining
compartment.
It will be understood that the various geometric shapes (e.g., sawtooth
shaped, knob shaped etc.) of the wall portions of the embodiments of the
present
invention illustrated in Figures 1-8 may be combined. For example, the knob
shaped cross-section illustrated in Figure 6 may be combined with the recessed
shaped cross-section in Figure 8 to form wall portions having both a recessed
portion and a knob shaped portion. It will also be understood that a
conventional
rip cord and/or a drain wire may be included in any of the embodiments of the
present invention.
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CA 02349327 2001-05-31
Attorney Docket 1 . 9040-7
Communications cables according to embodiments of the invention in
operation may reduce, and preferably minimize, cross-talk between the twisted
pairs of insulated conductors. Moreover, conununications cables according to
embodiments of the invention may reduce, and preferably minimize, capacitance
imbalance as desired for such cables.
The foregoing is illustrative of the present invention and is not to be
construed as limiting thereof. Although a few exemplary embodiments of this
invention have been described, those skilled in the art will readily
appreciate that
many modifications are possible in the exemplary embodiments without
materially
departing from the novel teachings and advantages of this invention.
Accordingly,
all such modifications are intended to be included within the scope of this
invention as defined in the claims. It is to be understood that the foregoing
is
illustrative of the present invention and is not to be construed as limited to
the
specific embodiments disclosed, and that modifications to the disclosed
embodiments, as well as other embodiments, are intended to be included within
the
scope of the appended claims. The invention is defmed by the following claims,
with equivalents of the claims to be included therein.
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